PHP Error regarding PayPal IPN

Hi.

I get these errors from your plugin:

2019-08-27T18:50:05+00:00 CRITICAL Uncaught Error: Call to a member function get_order_key() on bool in /home/armsportbu/domains/armsportbutiken.se/public_html/wp-content/plugins/woo-paypal-gateway/includes/paypal-ipn/class-woo-paypal-gateway-ipn-handler.php:303
Stack trace:
#0 /home/armsportbu/domains/armsportbutiken.se/public_html/wp-content/plugins/woo-paypal-gateway/includes/paypal-ipn/class-woo-paypal-gateway-ipn-handler.php(43): Woo_Paypal_Gateway_IPN_Handler->get_paypal_order('{"order_id":289...')
#1 /home/armsportbu/domains/armsportbutiken.se/public_html/wp-content/plugins/woo-paypal-gateway/includes/paypal-ipn/class-woo-paypal-gateway-ipn-handler.php(31): Woo_Paypal_Gateway_IPN_Handler->valid_response(Array)
#2 /home/armsportbu/domains/armsportbutiken.se/public_html/wp-content/plugins/woo-paypal-gateway/includes/class-woo-paypal-gateway.php(259): Woo_Paypal_Gateway_IPN_Handler->check_response()
#3 /home/armsportbu/domains/armsportbutiken.se/public_html/wp-includes/class-wp-hook.php(286): Woo_Paypal_Gateway->wpg_paypal_payment_api_ipn( i /home/armsportbu/domains/armsportbutiken.se/public_html/wp-content/plugins/woo-paypal-gateway/includes/paypal-ipn/class-woo-paypal-gateway-ipn-handler.php p? rad 303

Any idea why this happens? And can you fix it?